A laser diode is an electrically pumped semiconductor laser in which the active laser medium is formed by a PN or PIN junction of a semiconductor diode. Several laser diodes may be included on a single semiconductor substrate to form a laser diode bar. The laser diodes may be oriented in the same direction on the substrate to form an edge or facet from which light is emitted. The laser diode bars can be stacked between two conductive substrates, with the emitting edges oriented in the same direction, to form a two-dimensionally emitting surface. The laser diode bar stack may be used for pumping solid state lasers.